Effects of cigarette smoking on mucin production in human middle ear epithelial cells

Objective: Otitis media (OM) is the most common disease in preschool age children related to passive cigarette smoking as risk factor. In this study, we investigate whether the cigarette smoking can induce the inflammation in human middle ear epithelial cell, and cigarette smoke-induced inflammation can increase the expression of MUC5AC gene and protein that was known to play an important role in OM with effusion. Methods: After treatment of cigarette smoke solution (CSS) on immortalized human middle ear epithelial cells (HMEECs) with or without pretreatment by epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (AG1478), we observed expression of tumor necrosis factor-alpha (TNF-alpha), EGFR, MUC5AC mRNA by quantitative real-time reverse transcriptase-polymerase chain reaction (RTPCR) and EGFR, MUC5AC protein by western blotting. Results: Treatment of CSS increased expression of TNF-alpha mRNA dose dependently. Treatment of CSS upregulated the EGFR and MUC5AC mRNA in a time-dependent manner. CSS-induced upregulation of EGFR and MUC5AC mRNA was suppressed by the pretreatment of AG1478. EGFR and MUC5AC proteins were upregulated by the treatment of CSS and suppressed by the pretreatment of AG1478. Conclusions: Treatment of CSS on HMEECs increased the expression of MUC5AC mRNAs and proteins which play a major role in OM with effusion. (C) 2009 Elsevier Ireland Ltd. All rights reserved.